1. Field of the Invention
The present invention relates to a method of managing a plurality of radiation detectors, which are stacked together during use, a radiographic image capturing apparatus including a plurality of stacked radiation detectors, and a radiographic image capturing system that manages such a radiographic image capturing apparatus.
2. Description of the Related Art
In the medical field, there have widely been used radiographic image capturing apparatus, which apply radiation to a subject and guide the radiation that has passed through the subject to a radiation detector, which captures a radiographic image from the radiation. Known forms of radiation detectors include a conventional radiation film for recording a radiographic image by way of exposure, and a stimulable phosphor panel for storing radiation energy representing a radiation image in a phosphor, and reproducing the radiographic image as stimulated light by applying stimulating light to the phosphor. The radiation film with a radiographic image recorded therein is supplied to a developing device to develop the radiographic image, or the stimulable phosphor panel is supplied to a reading device to read the radiographic image as a visible image.
In an operating room or the like, it is necessary to read a recorded radiographic image immediately from a radiation detector after the radiographic image has been captured, for the purpose of quickly and appropriately treating patients. To meet such a requirement, there has been developed a radiation detector having a solid-state detector for converting radiation directly into electric signals, or converting radiation into visible light with a scintillator, and then converting the visible light into electric signals in order to read a detected radiographic image.
There is known a method of correcting data from a defective pixel of a radiation detector with data from pixels in the vicinity of the defective pixel in a radiographic image capturing apparatus, which incorporates such a radiation detector therein (see Japanese Laid-Open Patent Publication No. 2000-284059 and Japanese Laid-Open Patent Publication No. 2001-145617).
Specifically, Japanese Laid-Open Patent Publication No. 2000-284059 discloses the correction of data from a defective pixel in a radiographic image capturing apparatus, which incorporates a single radiation detector therein. Japanese Laid-Open Patent Publication No. 2001-145617 discloses the correction of data from a defective pixel in a radiographic image capturing apparatus, which incorporates two radiation detectors therein.
Japanese Laid-Open Patent Publication No. 2001-145617 states that when an X-ray detecting element of a front planar X-ray detector 51 (or a rear planar X-ray detector 52) becomes defective and causes an output error, a flaw correction processor 25 multiplies an output signal from an X-ray detecting element, in the same pixel position as the defective X-ray detecting element, of the rear planar X-ray detector 52 (or the front planar X-ray detector 51) by a coefficient in order to estimate an output signal from the defective X-ray detecting element, so as to perform flaw correction. Since the disclosed process uses the output signal of the defect-free X-ray detecting element in the same pixel position as the defective X-ray detecting element, it is considered to be more advantageous than the process disclosed in Japanese Laid-Open Patent Publication No. 2000-284059.
Radiation detectors should ideally be free of defective pixels. However, practically, it is highly difficult and hence costly to manufacture radiation detectors that are completely free of defective pixels. Expensive radiation detectors make it impossible to construct inexpensive mass-produced radiographic image capturing systems. One approach is to allow the radiation detectors to have certain defective pixels and correct output signals from such defective pixels. However, the process disclosed in Japanese Laid-Open Patent Publication No. 2001-145617 is problematic in that such a process cannot correct output signals from defective pixels if the defective pixels are in the same pixel position (coordinates) in the two radiation detectors.
There has been a demand for construction of a radiographic image capturing system, which allows defective pixels to initially be present to the extent that output signals therefrom can be corrected, i.e., a radiographic image capturing system that allows defective pixels to remain to a certain extent.